The present invention relates generally to the field of cooling systems for internal combustion engines. More specifically, the invention relates to blower scrolls for small engines, as used by rotary lawn mowers, pressure washers, secondary power generators, and the like.
Heat transfers from a combustion chamber within an engine to the surrounding cylinder, cylinder head, piston, crankcase, and other engine components. As such, engines are designed with cooling systems to prevent heat from concentrating in the components surrounding the combustion chamber. Cooling systems include lubrication systems, such as those that disperse motor oil within a crankcase, and air cooling systems. A blower fan serves as one type of air cooling system.
A blower fan is typically powered by an engine crankshaft. For example, the blower fan may be formed from fan blades extending from a flywheel that is spun by the crankshaft. The crankshaft spins the fan, which pulls air into the blower housing through a port. The spinning fan then drives the air to the walls of the blower. In some engines, a blower housing forms a scroll to direct the flow of air driven by the blower fan. An opening is formed in the blower scroll that directs air to cool the cylinder block and cylinder head. Typically, the cylinder and cylinder head include fins to enhance the heat dissipation into passing air. Also the directed flow of air helps to clear debris, such as loose grass clippings, from the crankcase and cylinder head.